This invention relates to a governor for an internal combustion engine. More specifically, the invention relates to an air vane governor.
Governors are known for internal combustion engines to govern engine speed. Different types of governors may be used in different engines, including flyweight governors and air vane governors. An air vane governor typically includes a rotatable flywheel or other support member that supports a fan having a plurality of spaced apart fins that rotate with the flywheel. As the fins rotate, they generate an air flow that is deflected by a pivotable air vane. A resilient member, such as a governor spring, opposes the movement of the air vane, such that the governed speed is determined by the interplay between the movement of the air vane and the spring force of the governor spring.
In typical air vane governors, the governor spring is attached to the linkage between the air vane and the throttle valve. When the spring is attached to the linkage, the spring exerts a side force on the linkage. This side force can cause the linkage to rotate or bind, which can affect the stability of the governor and cause problems, such as hunting or surging in the engine.
The speed of the engine typically drops when a load is applied to the engine. This drop in engine speed is called “speed droop” and is a characteristic of a particular engine. The speed droop is determined, in part, by the spring rate and tension applied to the governor spring. Speed droop causes a loss of horsepower in the engine and can affect the reliable function of the engine, especially under certain engine conditions.